Hydraulic unit



Dec. 8, 1964 w. L. KLINE 3,

HYDRAULIC UNIT Filed May 18, 1961 4 Sheets-Sheet l INVENTOR. WILL/AM L. KL/NE 1 By MAHONEY. MILLER & RAMBO BY I Mn ATTORNEYS.

Dec. 8, 1964 w. KLINE 3,160,109

HYDRAULIC UNIT Filed May 18, 1961 4 Sheets-Sheet 2 ILL/AM L. KL/NE BY MAHONEY, MILLER & RAMBO ATTORNE Y5.

Dec. 8, 1964 w. L. KLINE 3,

HYDRAULIC UNIT Filed May 18, 1961 4 Sheets-Sheet 3 INVENTOR. WILL/AM L. KL/NE BY MAHONEY, MILLER & RAMBO ArToR/vEYs.

W. L. KLINE HYDRAULIC UNIT Dec. 8, 1964 4 Sheets-Sheet 4 Filed May 18, 1961 INVENTOR. WILLIAM L. KL/NE BY MAHONEY, MILLER & RAMBO M I ATTORNEYS.

United States Patent 01 3,169,143? HYDRAULIC UNIT Wiiiiam L. Kline, Galena, Ghio Filed May 18, 1961, Ser. No. 111,075 The portion of the term of the patent subsequent to Mar. 31, 1981, has been diselairncd 2 Claims. (Cl. 103-162) My invention relates to a hydraulic unit. It has to do, particularly, with a fluid energy translating unit capable of use either as a pump or a motor. More specifically, it relates to a hydraulic unit comprising a cylindrical block or barrel, usually disposed with its axis vertical, carrying a plurality of pistons circularly arranged concentrically of the barrel axis and slidably mounted in the barrel for reciprocation parallel with the barrel axis in combination with an angularly adjustable or inclinable Wobble, swash or cam plate disposed coaxially of the barrel and operatively connected, usually by balls and sockets, to the pistons to ellect reciprocation of the pistons in response to relative rotation between the plate or cam and the barrel. The unit with which my invention deals further comprises means supporting the barrel for rotation about its axis and a valve plate engaged or mated With the upper end of the barrel, or end axially opposite the cam plate, and having a pair of ports or passages for connection, respectively, to a source of fluid and to a discharge line. The ports in the valve plate are registrable with ports or passages in the barrel which are individually connected to the piston chambers or cylinders in the barrel so that fluid will alternately be introduced into and discharged from each cylinder as the barrel is rotated relative to the cam plate.

This application is a continuation-in-part of my copending application Serial No. 857,284, filed December 4-, 1959, which issued as Patent No. 3,126,835 on March 31, 1964.

According to the invention disclosed in said copending application, the rotatable barrel is laterally or radially stabilized or supported by bearing means disposed coaxially within the lower end of the barrel, or end axially opposite the valve plate, and next adjacent the cam plate. The lateral or radial center line of the support hearing, which center line extends horizontally or at right angles to the barrel axis, is located at a predetermined distance below or axially beyond the point of intersection of the barrel axis and the general plane of the locus of the points of operative engagement between the pistons and inclined or angled cam plate. The resultant radial component of force between the pistons and cam plate will thus act on the moment arm, corresponding to the displacement of said lateral center line of the bearing from said point of intersection, to provide a barrel upsetting moment in one direction about the center of the barrel lateral support bearing. Further as disclosed in said copending application, the value of this barrel upsetting moment in said one direction is selected to correspond generally to a second barrel upsetting moment, acting in a direction opposite said one direction, and caused generally by centrifugal force acting on the centers of gravity of diametrically opposed pistons in the barrel. This second upsetting moment on the barrel occurs, during rotation of the barrel, because of the offsetting, longitudinally of the barrel axis, of the position of the centers of gravity of opposed pistons. Thus, by spacing the lateral support for the barrel from the intersecting point of the barrel axis and the general plane of the locus of the points of operative engagement of the pistons and cam plate on the opposite side of said intersecting point from said valve plate, the tendency of the barrel to tilt is substantially eliminated and the re sulting wear pattern is evenly distributed over the entire valving surface.

According to the present invention, the bearing means for laterally or radially supporting the barrel is of improved novel construction. As in the structure disclosed in my copending application, the drive for the barrel is from a shaft extending concentrically straight through the barrel and this shaft drives the barrel through a concentric torque tube or floating drive sleeve to aid in providing a substantially self-aligning drive for the cylinder barrel. Variable flexing or distortion of the shaft occurs at various loads and causes displacement of the axis of the shaft relative to the axis of the barrel. However, the bearing between the barrel and the shaft is so designed and arranged that in the event of this misalignment of the axes of the shaft and the barrel, binding between these members is prevented. The sleeve is keyed or splined to the cylinder barrel at the one end of the sleeve, the upper end, and the opposite end of the sleeve, that is the lower end, is keyed or splined to the shaft. .Adjaeent this end of the sleeve an annular stabilizing surface or support bearing is provided which is coaxial with and engage the inner surface of a depending skirt on the barrel. Thus, the spline connection between the sleeve and the shaft and the spline connection between the sleeve and the barrel are axially spaced at opposite ends of the sleeve. To permit the misalignment of the axis of the shaft relative to the axis of the barrel as discussed above, the outer surface of the lateral or radial support bearing is crowned in an axial or vertical direction so that it is provided with a spherical circumferential bearing surface. Any lateral distortion of the shaft which will produce slight misalignment of the axis of the shaft and the axis of the barrel, will be compensated for by a sli ht rocking of the crowned bearing surface relative to the surface of the barrel skirt with which it engages. Thus, the slight misalignment will not cause binding at the support bearing between the shaft and the barrel. Also, this crowned bearing arrangement will further aid in preventing tilting of the barrel relative to the mating valve plate which tends to separate them and cause blowofi and uneven wear at the valve plate. The crowned bearing in cooperation with the floating sleeve prevents the tilting movement of the barrel relative to the valve plate by converting it into a lateral or radial shifting movement of the barrel rather than a tilting movement so that the mating surfaces of the barrel and the valve plate remain in fiat intimate contact.

As disclosed in said copending application, lubricating passages are provided between the mating surfaces of the valve plate and the adjacent end of the barrel. According to the present invention these lubricating passages are supplied with hydraulic fluid under pressure by means of a booster pump driven by the main drive shaft which receives hydraulic fluid into the unit and boosts the pressure thereof. Hydraulic return of the pistons is provided for during the inlet stroke of the unit through connection of the piston cylinders in a closed hydraulic circuit controlled by the valve plate. This hydraulic return of the pistons is enhanced by making the pistons of stepped form so that the returning pressure will act more effectively thereon. Fluid expelled from the discharge side of the cylinders enters the inlet side forcing the pistons to follow the inclined or angled cam plate eliminating the problem of having the cooperating balls and sockets at the cam plate in tension with resulting wear thereof. The booster pump also maintains a hold-down pressure, acting on the stepped pistons, at a level sufiicient to overcome the reciprocating inertia of the pistons in the closed piston circuit to insure that tension between the balls and sockets, and resulting fatigue in the materials thereof, is substantially eliminated at all times as well as to maintain a continuously circulating supply of cooling and lubricating fluid for the unit. The hydraulic hold-down pressure acting on the stepped pistons also produces a reaction which will act on the barrel to enhance the contact of its end with the associated valve plate.

The accompanying drawings illustrate the preferred embodiment of my invention and illustrate the invention embodied in a hydraulic pumping unit having its main axis vertically disposed.

In these drawings:

FIGURE 1 is an axial or vertical sectional view through the pumping unit.

FIGURE 2 is an enlarged vertical sectional view taken through the unit substantially along line 22 of FIG- URE 1.

FIGURE 3 is an enlarged horizontal sectional view taken along line 3--3 of FIGURE 1 showing the valve plate and associated parts of the unit.

FIGURE 4 is a similar enlarged horizontal sectional view taken along line 4--4 of FIGURE 1 through the upper end of the barrel and associated parts of the unit.

FIGURE 5 is a detail in enlarged section taken along line S-5 of FIGURE 3 through the valve plate and associated parts.

FIGURE 6 is an enlarged horizontal sectional view taken along line 6-6 of FIGURE 1, mainly showing a ball-check valve arrangement associated with the booster pump.

FIGURE 7 is a similar enlarged horizontal sectional view taken along line 7-7 of FIGURE 2, mainly showing a valve port cap arrangement provided in association with the booster pump.

FIGURE 8 is an enlarged horizontal sectional view taken along line 8-8 of FIGURE 1 through the booster pump of the unit.

With reference to the drawings, and particularly FIG- URES 1 and 2, an exemplary fluid pressure energy translating device of a type with which this invention is concerned is shown with its axis vertical and generally comprises a hollow housing or body 10 on one end of which is mounted a port cap 12 and on the other end of which is mounted a base 14. The port cap 12 is provided with a fluid intake port or passage 16 and a discharge port or passage 18 leading into the housing 10. A shaft 20 is disposed generally coaxially within the housing 10 and is rotatably supported at one end by a suitable antifriction bearing 22, for example, a roller bearing, on the port cap 12. The lower end of the shaft 20 depends through the base 14 and may be coupled to suitable means, such as an electric or internal combustion motor, for rotating the same. The lower end of the shaft is rotatably carried by means of an antifriction bearing 22a in the base 14 and an oil seal 14a is provided on the base around the shaft.

Also disposed within the housing 10 is a generally cylindrical barrel or cylinder block 26 having a coaxial through-bore coaxially receiving the shaft 20. The barrel is provided at its lower end with a coaxial sleevelike extension or skirt 28, the inner diameter of which provides a bearing surface engaged on a support bearing on the shaft 20 provided by .an increased diameter land 30 on the shaft. A compression spring unit 19 is provided around the shaft above the bearing 22a and acts upwardly on the barrel skirt 28 to force the barrel upwardly relative to the shaft 20. A torque tube 32 is fitted coaxially over the upper portion of the shaft 20 and is coaxially received within the barrel bore and drivingly connected at its lower end of the shaft by a spline connection 21. The upper end of the torque tube 32 is drivingly connected to the barrel 26 by a spline connection 31, whereby upon rotation of the shaft 20 the barrel will be correspondingly rotated and the support bearing 30 will laterally or radially support the barrel coaxially of the shaft. It should be noted that the barrel 26 is radially spaced from the housing 10 and does not rotatably bear on any member in a radial direction. For a reason which will be hereinafter apparent, it is preferred that the spline connection 31 between the torque tube 32 and the barrel 26 and the spline connection 21 between the tube and the shaft 20 be constructed to permit slight radial displacement between these connected members while still maintaining a firm rotative drive connection.

The barrel 26 is further provided with a plurality of elongated cylinder chambers 34 circularly arranged concentrically about the barrel axis and extending parallel to the barrel axis. A plurality of pistons 36 are slidably received respectively within the chambers 34 for reciprocation parallel to the barrel axis. The barrel 26 is further provided with an intake and discharge passage 38 leading from each of the chambers 34 at the end thereof next adjacent the upper end of the barrel. Each of the passages 38 is directed to register at its outer end with a pair of passages 40 and 41 extending through a valve plate 42 disposed between the upper end of the barrel 26 and the port cap 12. As is usual in this type of device, each of the passages 40 and 41 in the valve plate arcuately extends only partially about the barrel axis, with these passages respectively communicating with the intake port 16 and discharge port 18 of the port cap 12, through their inlet and outlet passages 15 and 17 which align with the respective passages 40 and 41.

Disposed adjacent to but axially spaced from the lower end of the barrel 26 is an annular or ring-like cam plate 44 disposed coaxially of the barrel and mounted on an inclinable hanger 46 which is journalled as at 48 and 50 (FIGURE 1) for tilting relative to the barrel axis about an axis extending at right angles to the axis of the shaft 20. Further, as can be seen from FIGURES 1 and 2, the lower ends of the pistons 36 project outwardly of the corresponding end of the barrel 26 and are each provided with a generally spherical end 35 engaged in a generally spherical seat 55 in a shoe member 56 slidably engageable with the cam plate 44 to provide a universal operative connection between the cam plate and pistons.

In the operation of the device thus far described as a pump, rotation of the shaft 20 will correspondingly result in rotation of the barrel 26 relative to the inclined cam plate. 44 to effect reciprocation of the pistons 36 relative to the barrel. As the barrel 26 is rotated, fluid will be drawn in through the intake port 16, intake passage 40 in the valve plate 42, and the intake and discharge passages 38 in registry with the intake passage 40 in the valve plate 42. Further rotation of the barrel will cause these passages 38 to be moved out of registry with the intake passage 40 and be moved into registry with the discharge passage 41 in the valve plate, whereupon movement of the piston 36 toward the valve plate will cause pressurized fluid to be delivered outwardly through the discharge port 18 in the port cap. The angle of inclination of the cam plate 44 will determine the displacement of the pump and thus the quantity of fluid delivered per revolution. The displacement of the pump may, of course, be varied by varying the inclination of the cam plate.

As explained in said copending application, it is very important to locate the barrel support bearing 30 vertically so that its lateral center line is offset below the point on the axis of the shaft 20 at which the general plane of the locus of the spherical ends 35 of the pistons intersect the shaft axis. The location of this support bearing 30 a predetermined distance below said intersecting point or, in other words, on the opposite side of said point from'the valve plate end of the barrel 26, is selected so that for a given speed of rotation of the barrel 26, and inclination of the cam plate 44, any tendency of the barrel to tilt relative to the shaft axis is eliminated. Therefore, within a reasonable range of pump operation, such location of the barrel support bearing 30, will minimize the tendency of the barrel to tilt even though the opposing moments acting on the barrel, as discussed in said application, are not exactly equal. Thus, this assures more uniform contact of the endof the piston barrel 26 and valve plate 42, inasmuch as the tendency of the barrel to tip and separate or blow off from the valve plate is minimized or substantially eliminated. The tendency of the barrel to tilt even where a side or lateral loading occurs on the supporting land 30 is minimized by constructing the shaft 2% so that its diameter is not constant between its bearing supported ends and so that the point of maximum shaft deflection will occur at the midpoint 64 of the support land 39. It will be noted that the point 64 is substantially below where the general plane of the locus of the centers of the spherical ends 35 of the pistons intersects the shaft axis. Accordingly, lateral forces on the shaft will be reflected at the barrel support land 30 by a displacement of the land in a direction laterally of the shaft axis to tend to cause a lateral displacement rather than a tilting of the barrel axis. The torque tube 32 connecting the shaft 2t) and barrel 236 permits the barrel to shift radially while still maintaining the barre-l end and valve plate in intimate uncocked contact. Thus, the location of the barrel support land 30 below the median point of operative engagement between the pistons 36 and cam plate 44 substantially eliminates tilting of the barrel within a reasonable predetermined range of operation, while the preferred construction of the shaft 20 in cooperation with the torque tube 32 tends to convert any tendency of the barrel to tilt to a tendency to merely shift laterally or radially of the shaft axis so as to maintain the mating surfaces of the barrel and valve plate in proper uncocked relation.

In order to further decrease the effect of flexing of the shaft 20, which varies at different loads, on the tilting of the barrel 26, the barrel support bearing 30 is of special design and construction according to the present invention. As indicated best in FIGURE 2, the outer surface of the bearing is crowned in an axial or vertical direction to provide a circumferentially extending spherical bearing surface 39a. Any lateral distortion of the shaft 20 which will produce relative misalignment of the axis of the shaft 29 and the axis of the sleeve 32, will be compensated for by a slight rocking of the crowned bearing surface 30a relative to the inner surface of the barrel skirt 28 with which it contacts. Thus, such varying misalignment will not cause binding at the support bearing 39 between the shaft 29 and the barrel skirt 28. Also, this crowned bearing arrangement will further aid in preventing tilting of the barrel 26 relative to the mating valve plate 42 by converting it into a lateral or radial shifting movement on the barrel skirt 2% and the barrel 26 as a whole to prevent blow off at the valve Plate. Furthermore, the crowned bearing surface Stla cooperates with the floating sleeve 32 in preventing tilting of the barrel 26 to maintain the flat upper end of the barrel and the associated mating surface of the plate 42 in intimate contact providing an even wear pattern distributed over the entire mating surfaces. It is important that the spline between the shaft 2t and the torque tube 32 be at the lower end of the tube and closely adjacent the land or hearing 30 and that the spline connection between the barrel 26 and the tube 32 be. adjacent its upper end. The point of maximum deflection of the shaft, as indicated above, is adjacent the land 30 so this will produce a substantially lateral or radial movement of the tube rather than a tilting or cocking movement which, will, in turn, produce a lateral or radial movement of the barrel 26, rather than a tilting force, due to the spline connection at the upper end of the tube.

The pressurized fluid within the cylinders 34 will provide a force tending to urge the barrel 26 axially toward the valve plate 42. Also, there will be an oppositely directed hydraulic force acting on the end of the barrel in the area thereof bounded by the bleed passages 73 (FIGURE 2) in the valve plate 4-2. This latter forcetends to urge the barrel away from the valve plate. It will be noted that the plate 42 is non-rotatably fixed to the cap 12 by means of a dowel pin 39 (FIGURE 1).

v The net hydraulic force tending to urge the barrel 26 toward the valve plate 42 is referred to as the hydraulic clamp force. It is, of course, undesirable for the mating surfaces of the valve plate 42 and the barrel 26 to be spaced apart any substantial distance; however, it is desirable to provide an oil film between these surfaces to minimize wear of the parts. The hydraulic clamp forces urging the valve plate and barrel mating surfaces together tend to act in opposition to the provision of an oil film between the valve plate and barrel, and thus there is provided forced lubrication of the mating surfaces of the barrel and valve plate as will be explained in detail later. Forced lubrication of the contacting surfaces of the balls 35 and the shoes 56, as well as the contacting surfaces of the shoes and the cam 44, is accomplished, as indicated in FIGURE 1, by having a bleed passageway 43 extend through the lower end of each piston 36 and an aligning communicating passageway 47 extending through each shoe 56 to the surface of the cam 44. Thus, as each piston 36 reciprocates in its cylinder 34, oil will be forced between the contacting surfaces of the balls and shoes and the contacting surfaces of the shoes and cam.

According to the present invention, there is provided a booster pump unit 89 which maintains a pressure, acting downwardly on the stepped pistons 36, suflicient to overcome the inertia of the pistons in the closed piston circuit to insure that tension between the balls 35 and their retaining sockets in the shoes 56 is substantially eliminated. This tension, if present, tends to produce friction and wear at the ball and socket joints. Also, according to this invention, the booster pump serves as a part of the force lubricating system to provide cooling and lubricating oil to certain parts of the system such as the bearing 22, the sleeve 32, shaft 20, and other parts of the unit. This pump 80 is mounted on the cap 12 and is driven continuously by the up er end of the shaft 2% when such shaft is rotated.

The pump 80 is driven from the upper end of the shaft 24). For this purpose the lower end of the drive shaft 84 is positioned in a coaxial socket 87 formed in the upper end of the shaft 20. The shaft 84 carries a radial cross pin 85 at its lower end which slides vertically in a radial slot 86 (FIGURE 1) formed in the upper end of the shaft 20. A compression spring 88 is positioned in the bottom of the socket 87 and normally biases the shaft 84 upwardly.

The upper portion of the shaft 84 is hollow, being provided with a vertical bore 89 and this portion of the shaft carries a pump impeller element or gear 90 (FIG- URES 1, 2 and 8) which is keyed thereto by means of a pin 91. This element 9t) fits eccentrically within an internal gear pump element 92 with which it meshes. The element 92 is rotatably fitted within an eccentric collar 93 and this collar is positioned within a casing 94 for vertical sliding movement but is prevented from rotating therein by means of a dowel pin 95 fitting within opposed notches in the resepective outer and inner adjacent surfaces of the members 93 and 94. As indicated by the arrow in FIGURE 8, the pump elements 90 and 92 rotate clockwise. Below the pump elements 90 and 92 is a port plate 96 which is mounted in the casing 94 for vertical movement therein and is in concentric surrounding relationship to the shaft 84- and can slide vertically thereof. A collar type spring 97 between the bottom of the plate 96 and the bottom of the acsing 94 biases the port plate upwardly against the pump elements 90 and 92. The shaft 84 has an enlargement 98 at its upper end which provides a shoulder for limiting upward movement of the pump elements 90 and 92 relative thereto and this end rotatably fits within a downwardly opening socket formed concentrically in a valve port cap 99. The cap 99 is provided with a depending portion which fits into the upper open end of the casing 94. The main part of the cap 99 rests on the flange 100 at the upper end of the casing 94 and the casing and cap are nonrotatably mounted on the cap 12 by" means of bolts 101 which pass downwardly through openings 102 in the body of the cap 99, through aligning openings in the flange 100 of the casing, and are tapped into the upper end of the cap 12. The port plate 96, as indicated above, will be biased upwardly into proper contact with the pump elements 90 and 92 which will be moved up along with the shaft 84 and will properly contact the lower surface of the valve port cap 99, upward movement of the shaft being aided by the spring 88.

The cap 99 is provided with a central vertical bore 105 (FIGURES 2 and 6) which communicates at its lower end with the shaft bore 89 and at its upper end with a radial bore 106 in the body of the cap 99, the outer ends of the latter bore being closed by screw plugs 107 tapped therein. Inwardly of the vertical passage 105 in the bore 106 an annular valve seat member 108 is positioned for cooperation with a ball 109 which is normally held on the seat by a spring 110 engaged by a valve spring spacer 111 which is, in turn, engaged by the associated screw plug 107. Opposite the seat side of the member 108 in the cap 99 is a vertical passage or bore 112 which leads upwardly into the bore 106 and leading angularly from the latter bore is a bore or passage, one end of which is closed by a pin 114. The opposite end communicates with a vertical bore 115. This bore 115, at its lower end, communicates with a vertical passage 116 (FIGURE 1) formed by aligning bores in the casing flange 100, and the cap 12, and the valve plate 42. The lower end of the passage 116 aligns with a groove 116a formed in the lower surface of the valve plate 42 and extending angularly (FIGURE 3) for approximately 120. Leading downwardly through the cylinder barrel 26 and having their upper ends positioned to align with groove 11611 are three bores or passages 116b. The lower end of each of the passages 116!) communicates with an annular passageway 117 (FIGURES 1 and 2) formed in the inned surface of the shaftrand sleeve-receiving bore of the barrel 26 and covered by a band 118 between the sleeve 32 and the barrel bore. Leading downwardly and outwardly from this passageway 117 are outlet passages 119 (FIGURES l and 2) and each of these passages communicates with an associated cylinder chamber 34. The lower end of each passage 119 communicates with an annular recess 120 in the Wall of the chamber 34 which is so located that when the cooperating piston 36 is 'in its lowermost position, the recess is above the stepped or shouldered portion 121 of the piston.

Referring again to the passage 112 in the cap 99, it will be noted that its lower end communicates with an arcuate passage 122 (FIGURES 2 and 7) formed in the lower surface of the depending portion of the cap 99. A similar passage 122 is formed in this surface at the opposite side of the shaft 84 and both of these passages have their center of curvature at the axis of the shaft. Below the pump elements 90 and 92 similar arcuate grooves 122a are formed in the upper surface of the member 96 and it will be noted that the passages 122 are in vertical alignment with the passages 122a and both are in alignment with the space between the members 90 and 92.

Fluid is supplied to the booster pump unit from the main inlet port 16 of the hydraulic unit. For this purpose an inlet passage 125 (FIGURE 1) leads from the inlet 16 through the cap 12 and the wall of the booster pump casing 94 to an inlet 126 of the booster pump which communicates with one of the arcuate passages 122a. It will be noted also in FIGURE 1, that from the main outlet port 18 of the hydraulic unit a passage 127 leads downwardly through the cap and communicates with a passage 128 leading downwardly through the housing and provided for the purpose of supplying system pressure to the controls for the unit which are not shown and which include means for controlling the position of the hanger 46 and thereby controlling the inclination of the cam plate 44. It will be noted from FIGURE 2,

that the bleed passages 73 are in both the upper and lower surfaces of the valve plate 42 and from FIGURE 3 that they extend around the plate 360. The upper passages 73 are connected to the lower passages 73 by a series of angularly spaced, vertical bores 130. It will also be noted from FIGURE .2 that the lower surface of the cap 12 is provided with radial grooves or passages 131 so that oil forced down through the bearing 22 will pass outwardly to the upper bleed grooves or passages 73 and to vertical passages 132 (FIGURES 2 and 3) which lead downwardly, through the plate 42, past the upper end of the barrel 26, into the interior of the main housing 10. The lower passages 73 in the valve plate 42 allow fluid which leaks from the passages 38 to escape and thereby provides forced lubrication for the valve plate.

As indicated previously, the booster pump unit functions wtenever the shaft 20 is driven. The oil enters the pump at the inlet 126 and, as indicated by the arrows in FIGURE 2, is pumped outwardly therefrom through one of the grooves 122 and bore 112 into the bore 106. Ordinarily, it leaves the bore 106 through the passage 113 and passes downwardly through the bore and passage 115. The groove 116a in the lower surface of the valve plate 42 is of such extent and is so located that it communicates with the upper end of at least one of the passages 1161) at all times to apply pressure through the passageway 117 and through each of the outlet passages 119 to its associated stepped piston 1.21 as the piston is moved upwardly by the cam 44. Therefore, the position of the arcuate groove 116a is related to the position of the arcuate discharge passage 41 in the valve plate 42 so that pressure will be applied to each piston as the passage 38 at the upper end of its cylinder chamber 34 communicates with the passage 41. This eliminates tension at the associated ball 35 to prevent fatigue and minimize wear at that point. Thus, the stepped chambers between the pistons 36 and associated bores 34 are interconnected by the passages 119 and 117 in 'a closed system except for the passages 1161). Consequently, in this closed system, any pistons 36 that are displaced to contract the stepped chamber will cause an increase in pressure in that chamber and thus cause the other pistons of the closed system to move in the opposite direction. The purpose of the booster pump 80 is to supply make-up fluid to the system and provide a means of pressurizing the closed system to the desired pressure level. When fluid leaks into the closed system from the high pressure bores, the relief valve 109 of the pump will act to relieve the pressure acting on it through the passages 119, 117, 116b, 116a, 116,115 112, and 106 to prevent the closed system from becoming over-pressurized. Unseating the ball valve 109 will also, as indicated by the arrows in FIGURE 2, allow some of the oil to pass through the pump shaft bore 39 and an outlet 89a at the lower end thereof to the main shaft bearing 22. Also, some of this oil will pass downwardly through the bearing 22 to the bleed passageways 131 and 132 in the valve plate 42, the shaft 20 and the associated torque tube or sleeve 3-2, the barrel 26, and all other parts within the housing 10. Thus, all parts of the hydraulic unit are lubricated.

It will be apparent from the above that I have provided a hydraulic unit of the axial piston type in which the lateral support bearing for the drive shaft, in addition to its predetermined location, is crowned to prevent separation of the end of the barrel and the associated valve plate. Furthermore, in combination with the novel bearing structure, there is provided a booster pump which maintains pressure on the pistons during the return stroke of the pistons to prevent undue wear at the ball and socket joints and which provides continuously circulating cooling and lubricating fluid at the valve plate and other parts of the unit.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in What is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Having thus described this invention, what is claimed is:

1. In a fluid pressure energy translating device of the type described, a housing, a rotatable barrel disposed within the housing in concentric relationship thereto, a plurality of pistons slidably received in cylinders in the barrel and circularly arranged concentrically of the barrel for reciprocation parallel to the barrel axis, one end of each of the pistons projecting from the adjacent end of the barrel, a cam plate disposed adjacent one end of the barrel, spherical ball and socket joints between the projecting ends of the pistons and said cam plate to provide for reciprocation of the pistons in said cylinders relative to the barrel in response to relative rotation of the barrel and cam plate, said joints including shoes engaging said cam plate, a valve plate engaging the opposite end of the barrel for controlling the flow of fluid into and out of said cylinders, means providing lateral support for the barrel, said lateral support means including a shaft which supports said barrel and which in turn is supported by axially spaced bearings carried by the housing and an annular intermediate bearing surrounding said shaft, said annular bearing having a lateral center line spaced axially outwardly from the point of intersection of the shaft axis and general plane of the locus of the centers of the spherical balls at said projecting ends of the pistons and located in a plane between said plane of said centers and said cam plate, said annular bearing being curved in the direction of the axis of the shaft to provide a crowned surface, and a torque tube disposed axially over the shaft and within the barrel, said tube being splined at axially spaced positions axially inwardly of said shaft hearings to the shaft and barrel respectively and being splined at one end to the shaft adjacent said annular bearing and axially inwardly of said bearing and being splined at its opposite end to said barrel at the end of the barrel remote from the cam plate.

2. In a fluid pressure energy translating device of the type described, a housing, a rotatable barrel disposed in the housing in radially spaced relation thereto, a plurality of pistons slidably received in cylinders in the barrel and circularly arranged concentrically of the barrel for recip- 4 rocation parallel to the barrel axis, one end of each of the pistons projecting from the adjacent end of the barrel, a

cam plate disposed adjacent one end of the barrel and mounted on the housing for inclination about an axis at right angles to the barrel axis, spherical ball and socket joints between the projecting ends of the pistons and said cam plate to provide for reciprocation of the pistons in said cylinders relative to the barrel in response to rotation of the barrel relative to the cam plate, said joints including shoes engaging said cam plate, a valve plate engaging the opposite end of the barrel for controlling the fiow of fluid into and out of said cylinders, a coaxial cylindrical sleeve-like extension on said one end of the barrel, a drive shaft for the barrel extending coaxially through the barrel and said sleeve-like extension and rotatably supported by axially spaced bearings carried by said housing, a coaxial annular land intermediate the said axially spaced bearings of the shaft and coaxially engaged within said sleeve-like extension to laterally support the barrel coaxially of the shaft, said land having a lateral center line spaced axially outwardly from the. point of intersection of the shaft axis and general plane of the locus of the centers of the spherical balls at said projecting ends of the pistons and located in a plane between said plane of said centers and said cam plate, said annular bearing being curved in the direction of the axis of the shaft to provide a crowned surface, and a torque tube disposed coaxially over the shaft and within the barrel, said tube being splined at axially spaced positions axially inwardly of said shaft bearings to the shaft and barrel respectively and being splined at one end to the shaft adjacent said land and axially inwardly of said land and at its opposite end to said barrel at the end of the barrel remote from the cam plate.

References Cited by the Examiner UNITED STATES PATENTS 2,345,446 3/44 Baker 103-462 2,577,242 12/51 Grad 103162 2,817,954 12/ 57 Badalini 103162 2,915,985 12/59 Budzich 103162 2,925,046 2/60 Budzich 103-162 2,929,398 3/ 60 Purcell 103-162 3,046,906 7/62 Budzich 103-162 5 LAURENCE V. EFNER, Primary Examiner.

JOSEPH H. BRANSON, JR., Examiner. 

1. IN A FLUID PRESSURE ENERGY TRANSLATING DEVICE OF THE TYPE DESCRIBED, A HOUSING, A ROTATABLE BARREL DISPOSED WITHIN THE HOUSING IN CONCENTRIC RELATIONSHIP THERETO, A PLURALITY OF PISTONS SLIDABLY RECEIVED IN CYLINDERS IN THE BARREL AND CIRCULARLY ARRANGED CONCENTRICALLY OF THE BARREL FOR RECIPROCATION PARALLEL TO THE BARREL AXIS, ONE END OF EACH OF THE PISTONS PROJECTING FROM THE ADJACENT END OF THE BARREL, A CAM PLATE DISPOSED ADJACENT ONE END OF THE BARREL, SPHERICAL BALL AND SOCKET JOINTS BETWEEN THE PROJECTING ENDS OF THE PISTONS AND SAID CAM PLATE TO PROVIDE FOR RECIPROCATION OF THE PISTONS IN SAID CYLINDERS RELATIVE TO THE BARREL IN RESPONSE TO RELATIVE ROTATION OF THE BARREL AND CAM PLATE, SAID JOINTS INCLUDING SHOES ENGAGING SAID CAM PLATE, A VALVE PLATE ENGAGING THE OPPOSITE END OF THE BARREL FOR CONTROLLING THE FLOW OF FLUID INTO AND OUT OF SAID CYLINDERS, MEANS PROVIDING LATERAL SUPPORT FOR THE BARREL, SAID LATERAL SUPPORT MEANS INCLUDING A SHAFT WHICH SUPPORTS SAID BARREL AND WHICH IN TURN IS SUPPORTED BY AXIALLY SPACED BEARINGS CARRIED BY THE HOUSING AND AN ANNULAR INTERMEDIATE BEARING SURROUNDING SAID SHAFT, SAID ANNULAR BEARING HAVING A LATERAL CENTER LINE SPACED AXIALLY OUTWARDLY FROM THE POINT OF INTERSECTION OF THE SHAFT AXIS AND GENERAL PLANE OF THE LOCUS OF THE CENTERS OF THE SPHERICAL BALLS AT SAID PROJECTING ENDS OF THE PISTONS AND LOCATED IN A PLANE BETWEEN SAID PLANE OF SAID CENTERS AND SAID CAM PLATE, SAID ANNULAR BEARING BEING CURVED IN THE DIRECTION OF THE AXIS OF THE SHAFT TO PROVIDE A CROWNED SURFACE, AND A TORQUE TUBE DISPOSED AXIALLY OVER THE SHAFT AND WITHIN THE BARREL, SAID TUBE BEING SPLINED AT AXIALLY SPACED POSITIONS AXIALLY INWARDLY OF SAID SHAFT BEARINGS TO THE SHAFT AND BARREL RESPECTIVELY AND BEING SPLINED AT ONE END TO THE SHAFT ADJACENT SAID ANNULAR BEARING AND AXIALLY INWARDLY OF SAID BEARING AND BEING SPLINED AT ITS OPPOSITE END TO SAID BARREL AT THE END OF THE BARREL REMOTE FROM THE CAM PLATE. 